In 1970, Jim Estes made his first trek up to Alaska’s Aleutian Islands. He was greeted by an ocean filled with furry faces.
Everywhere the young biologist looked, there were sea otters — lollygagging on kelp beds, shelling sea urchins, exchanging their signature squeals. Back then, crowds of these charismatic creatures shrouded the sprawling archipelago, congregating in “rafts and bunches, as many as 500 at once,” said Estes, an ecologist at the University of California, Santa Cruz. “There were so many of them, we couldn’t keep track.”
Now, Estes said, more than 90% of those otters are gone. In just a few decades, this bustling civilization has withered into a ghost town. “You can travel down 10 miles of coastline and never see an animal,” he said.
The loss is more than cosmetic. In the Aleutians’ delicate seascape, otters hold the entire ecosystem together. As they have disappeared, the rest of the local food web has started to crumble — a process that’s been accelerated and compounded by climate change, Estes and his colleagues report in a paper published Thursday in the journal Science.
Without otters to keep them in check, populations of sea urchins have boomed, carpeting the sea floor in spiny spheres that mow down entire forests of kelp. Now, even the living, red-algae reefs on which the swirling stands of kelp once stood are in peril.
“These long-lived reefs are disappearing before our eyes,” said Doug Rasher, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in Maine and the study’s first author.
Softened by warming and acidifying waters, the coral-like structures have quickly succumbed to the urchins’ tiny teeth, which can annihilate years of fragile algae in a single bite.
The findings point to the importance of otters in the Aleutians, where the marine mammals act not just as predators, but protectors, maintaining biological balance through their voracious appetites. A single sea otter can scarf down nearly 1,000 sea urchins a day. “They eat them like popcorn,” Estes said.
“The amount of things they control in this ecosystem is pretty astonishing,” said Anjali Boyd, a marine ecologist at Duke University who wasn’t involved in the study. “For their size and how cute they are, they are aggressive eaters.”
Aleutian sea otters have been in flux before. Fur traders in the 18th and 19th centuries hunted the animals to the brink of extinction, allowing sea urchin numbers to skyrocket, Rasher said. Although the urchins eagerly descended upon the local smorgasbord of kelp, the bubblegum-pink reef beneath them seems to have persisted — in part because healthy algae produce a protective limestone layer that can thwart even the most determined grazers. When otter populations recovered after trapping was restricted, the reef rebounded, too.
But against the backdrop of climate change, Rasher said, the reef’s safety net is gone. In the past several decades, a glut of carbon dioxide in the atmosphere has acidified ocean waters, making it harder for algae to armor themselves. “The reefs are producing less dense skeletons,” Rasher said. “And temperature exacerbates that issue.”
To quantify the damage, Rasher and his colleagues braved high winds and freezing waters to collect samples over several years of the dwindling algae and analyzed them in the lab. When the oceans had been healthy, the team found, nips from urchins had barely scuffed the algae’s surface. But met with weakened reef layers, urchins excavated chasms several millimeters deep — the equivalent of up to seven years of growth.
From 2014 through 2017, some reefs shrank by up to 64%. Where algae had once coated the Aleutian sea floor like a swath of pink pavement, only patches remained.
Warmer temperatures also speed animal metabolism, driving urchins to eat even more enthusiastically than usual. “Given those two things happening simultaneously, it’s really getting hit from both sides,” said Alyssa Griffin, an ocean biogeochemist at the University of California, Davis, who wasn’t involved in the study.
The algae’s decline also seems to be speeding up. When the researchers grew urchins and algae under conditions that simulated the preindustrial past, the present and a projected future in the lab, they found that contemporary circumstances spurred urchins to gnaw away at algae up to 60% faster. Changes yet to come will likely prompt the grazers to pick up the pace even more, the team’s analysis showed, barring sweeping change in carbon emissions.
“Just seeing that trend is staggering,” Boyd said.
The findings add yet another example to the list of ecosystems being ravaged by an ever-warming world, and underscore how food chain alterations and climate change can disastrously collide. “Predator loss can impact the environment in ways we haven’t even thought of,” Griffin said.
But these hidden relationships might contain hints of remedies. Repatriating otters could help reefs in the near-term, Rasher said, perhaps “buying us time to get our act together in terms of curbing global carbon emissions.”
<a href=https://www.zxprinter.com/>Printing in China</a>.
That could be a difficult task, given the probable cause of the Aleutian Islands’ stunning vanishing of otters. Estes suspects that starving orcas — perhaps deprived of their preferred gray whale prey by industrial whaling — have turned in desperation to the little mammals, which they can gulp down by the hundreds or thousands a year. That could make it hard to sustain larger otter populations: Once introduced, they might just disappear all over again.
Estes, who is 74, hasn’t visited the Aleutians since 2015.
He doubts he will live to see the otters return. But he holds out hope that the islands will someday boomerang back to the breathtaking ecosystem he witnessed as a young man. “There was this incredible diversity,” he said. “It was spectacularly beautiful.”
2020年9月15日 18:52
that site
[url=https://empire-market.org/empire-market-url/]empire market link[/url]
2020年9月15日 17:56
More hints
[url=https://empire-market.org/tor-browser/]empire market url[/url]
2020年9月15日 17:40
Sexy teen photo galleries
http://freebihotporn.allproblog.com/?juliana
manimals porn pic download disney gals porn biography for porn star shefali chowdhury kids porn info tigers porn girlfriend
2020年9月15日 16:53
And were Materia Medica and Measurement. <a href="http://viassild.com/">discount sildenafil</a> Ypqpin clhxyw
2020年9月15日 16:26
why not find out more [url=https://empire-market.org/]empire market onion[/url]
2020年9月15日 15:53
Sexy pictures each day
http://loganporn.gigixo.com/?margarita
live action furry porn sexy secretary porn strip free porn mom boys young teens porn sucking cum nisa porn
2020年9月15日 14:35
Hot galleries, daily updated collections
http://vintage.porn.xblognetwork.com/?angelique
bomb mobile porn free amatur porn eightball gay porn wresting femdom cbt urethra sounding porn free ex porn tube
2020年9月15日 14:10
Teen Girls Pussy Pics. Hot galleries
http://mompornforipad.florafuckedporn.hoterika.com/?johanna
free gay porn clips for droids classic porn movies previews rosie paige porn ear porn pic free porn video downlodes
2020年9月15日 13:40
New hot project galleries, daily updates
http://wwwhotmailcom.ebenewoodkit.alexysexy.com/?essence
trini porn tv personality amy fisher pics porn free adult porn pages al porn hub free slutty emo porn
2020年9月15日 13:39
In 1970, Jim Estes made his first trek up to Alaska’s Aleutian Islands. He was greeted by an ocean filled with furry faces.
Everywhere the young biologist looked, there were sea otters — lollygagging on kelp beds, shelling sea urchins, exchanging their signature squeals. Back then, crowds of these charismatic creatures shrouded the sprawling archipelago, congregating in “rafts and bunches, as many as 500 at once,” said Estes, an ecologist at the University of California, Santa Cruz. “There were so many of them, we couldn’t keep track.”
Now, Estes said, more than 90% of those otters are gone. In just a few decades, this bustling civilization has withered into a ghost town. “You can travel down 10 miles of coastline and never see an animal,” he said.
The loss is more than cosmetic. In the Aleutians’ delicate seascape, otters hold the entire ecosystem together. As they have disappeared, the rest of the local food web has started to crumble — a process that’s been accelerated and compounded by climate change, Estes and his colleagues report in a paper published Thursday in the journal Science.
Without otters to keep them in check, populations of sea urchins have boomed, carpeting the sea floor in spiny spheres that mow down entire forests of kelp. Now, even the living, red-algae reefs on which the swirling stands of kelp once stood are in peril.
“These long-lived reefs are disappearing before our eyes,” said Doug Rasher, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in Maine and the study’s first author.
Softened by warming and acidifying waters, the coral-like structures have quickly succumbed to the urchins’ tiny teeth, which can annihilate years of fragile algae in a single bite.
The findings point to the importance of otters in the Aleutians, where the marine mammals act not just as predators, but protectors, maintaining biological balance through their voracious appetites. A single sea otter can scarf down nearly 1,000 sea urchins a day. “They eat them like popcorn,” Estes said.
“The amount of things they control in this ecosystem is pretty astonishing,” said Anjali Boyd, a marine ecologist at Duke University who wasn’t involved in the study. “For their size and how cute they are, they are aggressive eaters.”
Aleutian sea otters have been in flux before. Fur traders in the 18th and 19th centuries hunted the animals to the brink of extinction, allowing sea urchin numbers to skyrocket, Rasher said. Although the urchins eagerly descended upon the local smorgasbord of kelp, the bubblegum-pink reef beneath them seems to have persisted — in part because healthy algae produce a protective limestone layer that can thwart even the most determined grazers. When otter populations recovered after trapping was restricted, the reef rebounded, too.
But against the backdrop of climate change, Rasher said, the reef’s safety net is gone. In the past several decades, a glut of carbon dioxide in the atmosphere has acidified ocean waters, making it harder for algae to armor themselves. “The reefs are producing less dense skeletons,” Rasher said. “And temperature exacerbates that issue.”
To quantify the damage, Rasher and his colleagues braved high winds and freezing waters to collect samples over several years of the dwindling algae and analyzed them in the lab. When the oceans had been healthy, the team found, nips from urchins had barely scuffed the algae’s surface. But met with weakened reef layers, urchins excavated chasms several millimeters deep — the equivalent of up to seven years of growth.
From 2014 through 2017, some reefs shrank by up to 64%. Where algae had once coated the Aleutian sea floor like a swath of pink pavement, only patches remained.
Warmer temperatures also speed animal metabolism, driving urchins to eat even more enthusiastically than usual. “Given those two things happening simultaneously, it’s really getting hit from both sides,” said Alyssa Griffin, an ocean biogeochemist at the University of California, Davis, who wasn’t involved in the study.
The algae’s decline also seems to be speeding up. When the researchers grew urchins and algae under conditions that simulated the preindustrial past, the present and a projected future in the lab, they found that contemporary circumstances spurred urchins to gnaw away at algae up to 60% faster. Changes yet to come will likely prompt the grazers to pick up the pace even more, the team’s analysis showed, barring sweeping change in carbon emissions.
“Just seeing that trend is staggering,” Boyd said.
The findings add yet another example to the list of ecosystems being ravaged by an ever-warming world, and underscore how food chain alterations and climate change can disastrously collide. “Predator loss can impact the environment in ways we haven’t even thought of,” Griffin said.
But these hidden relationships might contain hints of remedies. Repatriating otters could help reefs in the near-term, Rasher said, perhaps “buying us time to get our act together in terms of curbing global carbon emissions.”
<a href=https://www.zxprinter.com/>Printing in China</a>.
That could be a difficult task, given the probable cause of the Aleutian Islands’ stunning vanishing of otters. Estes suspects that starving orcas — perhaps deprived of their preferred gray whale prey by industrial whaling — have turned in desperation to the little mammals, which they can gulp down by the hundreds or thousands a year. That could make it hard to sustain larger otter populations: Once introduced, they might just disappear all over again.
Estes, who is 74, hasn’t visited the Aleutians since 2015.
He doubts he will live to see the otters return. But he holds out hope that the islands will someday boomerang back to the breathtaking ecosystem he witnessed as a young man. “There was this incredible diversity,” he said. “It was spectacularly beautiful.”
2020年9月15日 12:22
Teen Girls Pussy Pics. Hot galleries
http://maninlatexporn.femdompornfree.instasexyblog.com/?tess
free porn pix lists free porn videos of big asses female clown porn teen dad porn ffx yuna sex porn
2020年9月15日 10:16
New super hot photo galleries, daily updated collections
http://hmongporn2009.fetlifeblog.com/?joanna
adult porn movies twenty blue tube videos porn judy neutron porn painfull crying porn sunshine tube porn
2020年9月15日 09:04
Daily updated super sexy photo galleries
http://pornteentaboo.stealpornstar.bestsexyblog.com/?jaylin
youtube cumshot porn asian girls groped porn video free amature quicktime porn 3d porn mac touring milf porn stars in ct
2020年9月15日 09:00
Sexy photo galleries, daily updated collections
http://realsexe.instasexyblog.com/?mariela
latest black porn movie porn choose your own adventure biggest male porn star candi evans porn spider chick porn
2020年9月15日 06:46
Sexy photo galleries, daily updated collections
http://freepornpic.seniorporn.hotblognetwork.com/?raina
dear diary cheating wifes porn porn lbfm paola couto porn movies prn brandie leesbian porn
2020年9月15日 05:22
My new hot project|enjoy new website
http://ebaymag.alexysexy.com/?madyson
first time gay porn auditions desi baby porn luscious the porn star free full lenght hentai porn movies porn industry jobs orlando fl
2020年9月15日 04:15
Hot new pictures each day
http://adultforumporn.hotnatalia.com/?tara
free phoenix homemade porn penis measuring porn free fat bbw porn video clips indian porn fre free homemade adult porn
2020年9月15日 04:14
Nude Sex Pics, Sexy Naked Women, Hot Girls Porn
http://lesbian.shower.bestsexyblog.com/?brianna
sexy porn titty fuck youporn awesome porn sites free evening movies free porn xxxdirty granny porn xxx illegal forbidden porn
2020年9月15日 03:08
Free Porn Galleries - Hot Sex Pictures
http://ameteurpornpic.hottestpictures.relayblog.com/?emily
porn star lounge heather hunter porn actress free wii porn couch porn suck cock naruti y hinata en porn
2020年9月15日 01:46
Sexy photo galleries, daily updated pics
http://littlemistress.allproblog.com/?jaiden
fishnets free porn thumbnail porn picts mom son havin threesome porn loud nasty gay porn free home grown porn